Marxavi Angel Martinez, 23, was arrested at the library in Alamance County, the Raleigh News & Sentinel reports. She faces four federal felony charges.

Sheriff Terry Johnson, who has been aggressively targeting illegal immigrants, has said that the arrest was related to an investigation of the county health department. The state Bureau of Investigation has been looking into allegations that health department employees wrote notes excusing illegal immigrants from work using names different from those on their medical records.

Randy Jones, a spokesman for the sheriff said that Martinez lied on her application to work at the library.

"That is not a situation where you can say, 'We're not going to tell anybody,' " Jones said.

But people who know Martinez say that a young woman in her situation should not be treated like a criminal.

"To go after productive citizens who have been our neighbors and friends for years? It's insane," said Marilyn Tyler, a retired librarian. "We can't just stand by and let this happen."